The present invention relates to auger type poultry chillers using a chilled water bath to chill poultry carcasses, and in particular, to the type of poultry chiller having means to introduce pressurized air into the chiller to agitate the chilled water bath.
In the processing of poultry for human consumption, it is necessary that the slaughtered, eviscerated poultry carcasses be chilled as rapidly as possible. Various types of poultry chillers to accomplish the chilling of freshly killed poultry are known in the art. Poultry chillers typically employ chilled water to reduce the temperature of the poultry carcasses. For example, U.S. Pat. No. 4,788,831 discloses a drag type chiller in which a series of moving rakes advance the poultry carcasses through a tank of chilling liquid.
Another type of chiller is the auger type as disclosed in U.S. Pat. No. 5,868,000 which discloses a poultry chiller in which an auger having a series of flights that form a generally helical structure that when rotated moves the poultry carcasses through a chilled water bath. Similar chillers are disclosed in U.S. Pat. Nos. 4,860,554 and 5,484,615.
In the auger type chiller, the auger rotates within a trough shaped housing. The poultry carcasses enter at one end of the housing and are removed at the opposite end of the housing. Water is chilled externally, for example, by an ammonia refrigeration system through a heat exchanger. The chilled water enters the chiller housing at the end from which the chilled poultry carcasses are removed, and the water circulates in the opposite direction to the movement of the poultry carcasses, exiting the chiller, after being warmed by contact with the poultry carcasses, at the end where the carcasses are introduced. The warmed water is again chilled by the refrigeration system and recirculated through the chiller.
As noted in U.S. Pat. No. 5,868,000, one problem with the auger type chiller is the tendency of the poultry carcasses to clump or bunch up between successive flights of the helical auger. The solution disclosed in this patent is to provide the auger with a set of structures, which break up the clumps and distribute the poultry carcasses more evenly between the flights of the auger. Another solution to this problem that has been adopted in the art is to provide jets of compressed air which are introduced into the bottom of the chiller. The pressurized air agitates the chilled water and prevents clumping of the poultry carcasses. In order to supply the pressurized air to the chiller, it is typical to provide an air header which is mounted longitudinally outboard of the upper edge of the housing of the chiller. The air header is provided with a supply of pressurized air. From the air header, a series of air hoses are led to inlets on the bottom of the chiller housing.
Various other means of introducing pressurized air or other fluids into the bottom of a chiller housing are known in the art. Examples are particularly common from the art of sterilizing or decontaminating chiller water and the poultry carcasses therein. Examples include U.S. Pat. Nos. 4,827,727; 4,849,237; and 5,484,615.
While there are advantages to locating the air header at the upper edge of the chiller housing, there are severe disadvantages which generally fall into two groups. First, the location of the air header longitudinally outboard of the upper edge of the housing places the air header into a space which is generally used for access to the equipment. For example, it may be necessary to construction an elevated catwalk so that personnel have access to the chiller for observation and maintenance. Such an exposed location however both interferes with access to the chiller and places the air header in a location where it is exposed to damage from personnel and equipment moving along the elevated catwalk. The points of connection of the air hoses to the air header are particularly vulnerable and may easily be broken.
A second major problem with the placement of an air header outboard of the upper edge of the chiller housing is structural. Poultry chillers, while quite heavy constructions, are normally built with limited structural stiffening. The upper edge, for example, is typically formed by bending the sides of the housing into an inverted U-shape with a flattened top surface. Such an arrangement provides a minimum of structural strength to the housing and is adequate for most purposes if the chiller is stationary and if the upper edge of the housing is required to support little more that its own weight. Such an arrangement is completely inadequate, however, if the housing is required to provide the strength and rigidity to support other structures. One such structure is the support structure for the auger itself. As may be understood the auger is a large unwieldy structure which must be adequately supported, at least at each end, for rotary motion. The supporting structure must also assist in resisting the thrust load engendered by the motion of the auger through the chilled water and poultry carcasses. For proper alignment and proper support it is desirable that the support structure for the auger be located above and rest upon the housing itself. The support structure for the augers must also be capable of adjustment to place the auger in the proper position within the housing and with its shaft properly aligned with its motor and bearings.
The limitations of the prior art are overcome by the present invention as described below.